Allow render of reMarked instance to be called multiple times + other fixes

- Allow render mothe of reMarked instance to be called multiple times
- Fix rendering of links to images in reference list (missing !)
- Fix handling of img src attribute being output to reference list.
Reinstate default config

Also removed console.log() call.
Merge pull request #1 from RoryH/patch-1

Fix link/images reference behaviour, allow render method of reMarker instance be made multiple times without issue.